1. Field of the Invention
The present invention relates to a lighting device for a display device, a display device and a television receiver.
2. Description of the Related Art
A liquid crystal display device used in a television receiver typically includes a liquid crystal panel and a backlight arranged on the backside of the liquid crystal panel. One of the known backlights includes light sources such as cold cathode tubes, a chassis arranged to contain the light sources and having an opening on the light emitting side, and optical members arranged to cover the opening of the chassis and having functions such as a function for diffusing or converting light from the light sources into more uniform flat light.
The optical members often include a diffuser plate, which includes a number of diffusing particles distributed over a light transmissive base member of a predetermined thickness. For example, the diffuser plate can be supported by a support portion provided on the chassis side, so that the peripheral edge thereof rests on the support portion. In this case, the inner portion of the diffuser plate or the portion on the inner side of the peripheral edge can be supported from the chassis side, by support members mounted to the chassis (as shown in JP-A-2004-265709, for example).
In some cases, the above diffuser plate may arch or deform resulting in warpage in response to increases in the internal temperature of the chassis due to heat from the lighted light sources, so as to bulge toward the light sources. The support members can support the deformed diffuser plate from below (i.e., from the light source side), so that a distance is maintained between the diffuser plate and the light sources. However, the diffuser plate may continue to deform causing further warpage, which results in deformation of the support members in the case of the above supporting structure. In the course of deformation of the support members due to the diffuser plate having largely deformed resulting in warpage, friction will occur between the diffuser plate and the support members, which may cause frictional noise. After further deformation of the support members, the support members may return to the original state as a result of the elastic restoration. At that time, friction will also occur between the diffuser plate and the support members, which may also cause frictional noise. The frictional noise thus generated is extremely uncomfortable for users, and can lead to reduction in quality of the backlight and therefore of the liquid crystal display device that includes the backlight.